The present invention relates to a lot managing technique in semiconductor device carrying facilities; and in particular to a system, process, apparatus and recording medium for achieving an automation of the carrying of, for example, a lot of special purpose wafers used for monitoring dust, which are not processed in semiconductor manufacturing facilities.
In association with an advance in very fine fabrication technology of semiconductor devices, the problem of foreign material such as particles (dust) has become more serious. Clean rooms of the semiconductor manufacturing factory are equipped with detecting instrument for checking the dust in an air cleaning system, air conditioning system and the air depending upon the class of required cleanness. The dust having a size of, for example, about 0.18 xcexcm or less, which is adhered to wafers is measured by a dust measuring instrument (also referred to as xe2x80x9cwafer foreign material inspecting instrumentxe2x80x9d) relying upon light scattering method using laser light etc.
Modularization of the clean rooms in the semiconductor factory has been promoted basically for each process. Modules are usually partitioned by bays. Carrying of lots of wafers between steps (between stockers) and within a step is automatically conducted by means of inter-step (i.e., interoperation) carrying vehicle and interoperation carrying robot, respectively. FIG. 9 is a diagram schematically showing an exemplary floor in a clean room for manufacturing semiconductor devices.
Referring to FIG. 9, reference a denotes the whole of line. The whole of line is divided into areas b for each step. Each area b comprises a plurality of manufacturing apparatus c and at least one stocker or stock bin d (also referred to as xe2x80x9cclean stocker). Carrying of a lot (one lot comprises, for example, 25 wafers) within an area b is conducted by an in step carrying robot e. The lot of wafers accommodated in a carrier is carried on a path g disposed between the stockers d by an interoperation carrying vehicle h. The interoperation carrying vehicle h is adapted to carry the lots between different areas, and takes the lots from the stocker d and moves along a path g and gives the lots to the stocker d at different area. The manufacturing apparatus (in a step is adapted to process the wafers of the lot and includes various apparatus for washing, diffusion, oxidation, exposure, developing processes, CVD (chemical vapor deposition), RIE (reactive ion etching) for different steps. The path g (also referred to as xe2x80x9cinteroperation carrying facility clean wayxe2x80x9d) comprises, for example, an elevated rail way. Receiving and issuing of wafers to and from the stockers are conducted by means of lifter.
A conventional method of measuring the cleanness of the carrying facilities in a clean room includes measuring dust by carrying wafers for monitoring dust between steps. As is described in, for example, Japanese Patent Kokai Publication 10-199945, a measuring operator sets wafers for monitoring dust on a carrier, places them into a stocker together with the carrier, sequentially carries the wafers used for monitoring dust which are accommodated in the carrier between stockers, takes the carrier out from a final stocker to a wafer dust measuring instrument by a platform car for measuring the dust.
A conventional system for controlling carrying of wafers used for monitoring the dust will be described with reference to FIG. 8. Referring now to FIG. 8, the carrying control system comprises a host computer 10xe2x80x2 for production managing, a carrying host computer 20xe2x80x2, and stockers (stock bins) 40. An interoperation carrying vehicle 50 for carrying a carrier 52 which accommodates, for example, one lot of wafers 51 is advanced on a path (rail: g in FIG. 9) disposed between the stockers 401 and 402 at different areas. Interoperation carrying controllers 301, 302 are controllers which are provided for the stockers 401, 402, respectively, and are in communication with the carrying host computer 20xe2x80x2 and host computer 10xe2x80x2, respectively, via a network 60. The carrying host computer 20xe2x80x2 receives and transmits necessary control data between the interoperation controllers 301 and 302 for controlling automatic carrying of wafer lot from the stocker 401 to the stocker 402 (between steps).
FIG. 10 is a diagram showing an exemplary configuration of the database which the host computer 10xe2x80x2 and the carrying host computer 20xe2x80x2 include. Referring to FIG. 10, the host computer 10 includes a lot table 11 which manages the processing conditions and the advance of each lot for registering its purpose in relation to the lot ID. The lot table 11 is a table which is a list of all lots registered in the host. Registration of lots is conducted by a managing operator. The lot IDs and the purposes (applications) of lots are registered in the lot table 11.
The carrying host computer 20xe2x80x2 is adapted to coordinate the carrying of lots and to instruct to carry the lots to the stocker 40 and includes a storage lot table 21 which is a list of lots stored in the stocker 40. The storage lot table 21 includes the lot ID and the purpose of the lot stored in the stocker as one entry. The storage lot table 21 is a table which is a list of the lots stored in the stocker. The carrying host computer 20xe2x80x2 automatically updates its contents at will in response to a report from the stocker (receipt/issue notification information).
The stockers 40 are storage warehouses each of which stores a plurality of lots to be processed and is adapted to control the receipt/issue and carrying of the lots in response to a carrying instruction from the carrying host computer 20xe2x80x2.
FIG. 12 is a flow chart showing the processing procedure of the conventional carrying control system.
The lots of the special purpose wafers which are not processed in the manufacturing apparatus, such as the lots of wafers used for dust monitoring are treated as special lots and are discriminated from the product lots of wafers which are processed in a wafer processing apparatus. The lot IDs and the purposes are registered in the lot table 11 of the host computer.
The special lot is received by the stocker 40 (step S20). The lot ID of the received lot is reported to the carrying host computer 10xe2x80x2 from the stocker 40 and the stocker which stores the special lot is also reported to the carrying host computer 201. The carrying host computer 20xe2x80x2 updates the lot ID of the special lot and registers the updated lot ID in the storage lot table 21 corresponding to the stocker (step S21).
The carrying host computer 20xe2x80x2 conducts the task control of the carrying of the lot in interest in the same timing relationship when it receives the report of the lot ID from the stocker 40.
The host computer 10xe2x80x2 determines the purpose of the lot in interest with reference to the lot table 11 based upon the reported lot ID (step S22). At this time, the in-process stocker (i.e. next stocker to which the lot is to be carried) is determined depending upon the processing condition of the lots whatever purpose or use the lot has. Accordingly, dummy processing conditions for the special lot (not shown in FIG. 10) are preset in the lot table 11 differently from the product lot. The next step of the product lot for the current step is determined in accordance with preset processing conditions (processing pattern). In contrast to this, the dummy processing condition become in-process state for any stockers irrespectively of order of steps.
The operator selects the special lot stored in the current stocker from an operation terminal (not shown) of the carrying host computer 10xe2x80x2 based upon the lot ID and inputs a carrying instruction for carrying the selected special lot to desired next stocker from the current stocker (step S23). Since the special lot is carried to a manufacturing apparatus in a step for processing as mentioned above, it is managed under dummy conditions and the operator can select any stocker as next in-process stocker.
The carrying host computer 20xe2x80x2 outputs an instruction to carry the lot to relevant stocker (step S24).
The stocker 40 automatically issues specified special lot in response to a carrying instruction from the carrying host computer 20xe2x80x2 and updates the storage lot table 21 (step S25). The issued lot is carried to the specified next stocker by an interoperation carrying vehicle (step S26) so that it is received by a stocker in interest.
If the operation reaches at a final step by repeating the above-mentioned steps 20 to 26, the lot is stored by the stocker at its step. The special lot which has reached the final step is taken out from the stocker and is carried to a dust measuring instrument by a platform car, so that the measurement on dust adhered to wafers is conducted in the dust measuring instrument.
FIG. 11 is a diagram explaining the carrying operation of a special lot from a stocker X to a stocker Y in a conventional carrying control system. The operator inputs a carrying instruction for carrying the special lot stored in the stocker X to the stocker Y by operating a terminal of the carrying host computer 10xe2x80x2 (1). The carrying host computer 10xe2x80x2 sends an carrying instruction to the stocker 4 in response to the carrying instruction (2). The interoperation carrying vehicle carries the lot to the stocker Y (3). When the special lot is received by the stocker Y, a carrying completion report is noticed to the carrying host computer 10xe2x80x2 (4).
However, the above-mentioned carrying control system has the problems which will be described.
A first problem is that it is necessary for the operator to manually input a carrying instruction from the operation terminal of the carrying host computer on each carrying of the special lot from the stocker, that is each interoperation carrying, resulting in that the advance in carrying of the special lot between steps is managed by the operator. As a result, the burden of the operation on the operator is high and the working efficiency is low. In particular, if the special lot is carried through a number of stockers, or is cycled through the carrying facilities (path) many times, the working burden is greater and the possibility of wrong input may increase in conventional carrying control system.
This reason is as follows: Although the special lot is managed by the storage lot table 21 of the carrying host computer 20xe2x80x2 as is similar to the product lot on carrying between steps, that is, on receipt and issue to and from the stocker, a function to automatically advance the special lot to next step is not provided when a report of carrying completion ((4) in FIG. 11) is received from the stocker. Accordingly, it is necessary for the operator to input a carrying instruction from a terminal of the carrying host computer, whenever the special lot is carried between the steps. For example, if the special lot is carried through the stockers 1, 2, . . . 7 and 8 on a line xe2x80x9caxe2x80x9d in FIG. 9, the operator has to input a carrying instruction to next stocker from the terminal (not shown) of the carrying host computer 20xe2x80x2 whenever the special lot is received by each stocker.
If in order to solve the first problem, the system is configured to register and manage a carrying completion report which is sent to the host computer so that the report is assumed to indicate the completion of the interoperation carrying, that is, carrying between steps, when the carrying of the special lot to the stocker is completed, a second problem would occur. In other words, the carrying completion report may be registered as one step for usual product lot. As a result, a number of useless steps should be registered and managed. This results in a low utilization of storage area in efficiency a complicated control, and a longer processing time, ultimately leading to lowering of the performance.
For example, Japanese Patent Kokai Publication 07-085154 discloses a system configuration. In this configuration, a reservation of working initiation of a special lot is registered when an operator makes a reservation of working initiation by selecting a special lot from a lot file and when processing turn comes to the special lot, an interoperation carrying instruction is issued so that the special lot is taken from the stocker to a manufacturing apparatus in process and the special lot is subjected to processing by a desired manufacturing apparatus without necessity of an operator to manually carry and set the special lot to the manufacturing apparatus and/or to input processing conditions to the manufacturing apparatus, as a lot managing apparatus which automatically carries the special lot similarly to usual lot while readily registering the special lot while readily registering the special lot used for measuring pollution in a clean room and for achieving special object in a lower rank computer by eliminating the necessity of registering in a central line control computer of the lot managing apparatus. The above-mentioned Japanese Patent Kokai Publication 07-085154 discloses no detailed means and structure on how automatic carrying of the special lots between stockers (stations) can be conducted. Implementation of automatic carrying is never considered without increasing the registration items of the product lots on the host computer.
Therefore, there is much to be desired in the art in view of the above-mentioned problem. It is an object of the present invention to provide a system, process and apparatus which automates lots of special purpose wafers between stockers and a recording medium which records thereon a control program which implements the same system. The other objects, features and advantages of the present invention will readily become more apparent to those skilled in the art from the following description of the embodiments.
The above object is achieved generally by the features of claim 1.
That is there is provided a carrying control system, characterized in that a carrying pattern defining a carrying path for each of special purpose lots comprising wafers which will not be processed in production facilities is preliminarily stored in a storage unit which is accessed from a carrying host computer which manages the control of carrying facility,
that the carrying host computer, which receives a report of the completion of carrying relating to the special purpose lot or lots from one of stockers when the special purpose lot or lots are received by the one of the stockers, is adapted to advance the carrying step of the special purpose lot or lots and in accordance with a carrying pattern to determine a next stocker corresponding to the special purpose with reference to the storage unit so that it sends an instruction to carry the special purpose lot or lots to the one of the stockers, and that the special purpose lot or lots are automatically carried from a stocker constituting a starting point of the carrying pattern which is preliminarily defined for the special purpose lot or lots to a stocker constituting a final point of the carrying pattern.
In one aspect of the present invention, there is provided a carrying control system carrying comprising:
stockers for storing therein special purpose lots comprising wafers which will not be processed in production facilities, or the special purpose lots and usual lots comprising wafers which will be processed by production facilities and a carrying host computer for controlling automatic carrying of lots in carrying facilities, in which the carrying host computer comprises a storage unit for registering carrying patterns which define a carrying path or paths for special purpose lots, the computer receives a report of receipt of the special purpose lot or lots by the one of stockers transmitted from the one of the stockers when the special purpose lot or lots are received by the one of the stocker in the carrying pattern, initiating a counting means and assuming that processing of the special purpose lot or lots stored in the stocker are completed when a result of count in the counting means shows the lapse of a predetermined period of time, determining next stocker to which the special purpose lot or lots are to be carried next in accordance with the carrying pattern corresponding to the special purpose lot or lots stored in the storage unit, and sending to the one of the stockers which stores the special purpose lot or lots a carrying instruction for carrying special purpose lot or lots to a next stocker.
In a further aspect of the present invention, there is provided a process for controlling the carrying of special purpose lots. The process comprises the steps of:
preliminarily storing a carrying path for each of special purpose lots comprising wafers which will not be processed in production facilities in a storage unit which is accessed from a carrying host computer which manages the control of carrying facilities,
receiving a report of completion of carrying relating to the special purpose lot or lots from one of stockers when the special purpose lot or lots are received by the one of the stockers,
initiating a timer and assuming that processing of the special purpose lot or lots stored in the stocker are completed upon the lapse of a predetermined period of time after the receipt of the special purpose lot or lots by one of the stockers,
determining a next stocker in accordance with a carrying pattern corresponding to the special purpose with reference to the storage unit so that it sends an instruction to carry the special purpose lot or lots to the one of the stockers, and
automatically carrying special purpose lot or lots from a stocker constituting an starting point of the carrying pattern which is preliminarily defined for the special purpose lot or lots to a stocker constituting a final point of the carrying pattern.
In a carrying control apparatus for controlling automatic carrying of lots among stockers which store special purpose lot comprising wafers which are not processed in production facilities or lots comprising the special purpose lot or lots and a lot or lots of wafers which are processed in production facilities, a program product to cause a computer constituting the carrying control to execute the operations of:
(a) initiating a timer in response to a report of receipt of the special purpose lot or lots which are received by one of the stockers when the one of the stockers receives the special purpose lot or lots;
(b) determining a step to which the special purpose lot or lots are to be carried in accordance with a carrying pattern corresponding to the special purpose lot, stored in a storage by assuming that processing of the special purpose lot or lots of the lots received by the stocker is completed based upon a result of counting in the timer when a predetermined period of time has lapsed since the special purpose lot or lots are received by the one of the stockers; and
(c) sending to the stocker which stores the special purpose lot or lots a carrying instruction to carry the special purpose lot or lots to the determined next step.
Other aspects and/or features of the present invention are mentioned in the appended claims, the entire disclosure thereof being incorporated herein by reference thereto.